Calculation using a trendline

[Chris]

When I calculate a trendline, I get a 6 degree polynomial. How do I calculate
a value using this formula? I have no idea how to compute the capital "E" - I
don't think it's Euler's number and it doesn't look like scientific notation
to me...

"y = -1E-07x^6 + 0.0016x^5 - 7.9878x^4 + 20857x^3 - 3E+07x^2 + 2E+10x - 8E+12
"
Thanks for your help!

 

[ShaneDevenshire]

Hi,

Correct it's not an Eulier number it's just a notation Excel uses
10E2 is 10x10^2

Move to a cell and type 10E2
Move to another cell and type 10E-2

I think it will all become clear.

If this helps, please click the Yes button.

 

[Joel]

If you would put it in a worksheet for calculation you would get this

= -0.0000001*(B1^6) + 0.0016*(B1^5) - 7.9878*(B1^4) + 20857*(B1^3) -
30000000*(B1^2) + 20000000000*(B1) - 8000000000000

I entered -1E-07 and excel converted it to -0.0000001

 

[Mike Middleton]

Chris -

(1) Using a polynomial of order more than 2 or 3 often results in
overfitting. Interpolation may (or may not) be useful, but extrapolation is
likely to be useless.

(2) Here's one way to calculate y for a new x:

=TREND(known_y,known_x^{1,2,3,4,5,6},new_x^{1,2,3,4,5,6})

- Mike Middleton
http://www.DecisionToolworks.com
Decision Analysis Add-ins for Excel